fs/xfs/linux-2.6/xfs_xattr.c

   1 /*
   2  * Copyright (C) 2008 Christoph Hellwig.
   3  * Portions Copyright (C) 2000-2008 Silicon Graphics, Inc.
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License as
   7  * published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it would be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write the Free Software Foundation,
  16  * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  17  */
  18
  19 #include "xfs.h"
  20 #include "xfs_da_btree.h"
  21 #include "xfs_bmap_btree.h"
  22 #include "xfs_inode.h"
  23 #include "xfs_attr.h"
  24 #include "xfs_attr_leaf.h"
  25 #include "xfs_acl.h"
  26 #include "xfs_vnodeops.h"
  27
  28 #include <linux/posix_acl_xattr.h>
  29 #include <linux/xattr.h>
  30
  31
  32 static int
  33 xfs_xattr_get(struct dentry *dentry, const char *name,
  34                 void *value, size_t size, int xflags)
  35 {
  36         struct xfs_inode *ip = XFS_I(dentry->d_inode);
  37         int error, asize = size;
  38
  39         if (strcmp(name, "") == 0)
  40                 return -EINVAL;
  41
  42         /* Convert Linux syscall to XFS internal ATTR flags */
  43         if (!size) {
  44                 xflags |= ATTR_KERNOVAL;
  45                 value = NULL;
  46         }
  47
  48         error = -xfs_attr_get(ip, name, value, &asize, xflags);
  49         if (error)
  50                 return error;
  51         return asize;
  52 }
  53
  54 static int
  55 xfs_xattr_set(struct dentry *dentry, const char *name, const void *value,
  56                 size_t size, int flags, int xflags)
  57 {
  58         struct xfs_inode *ip = XFS_I(dentry->d_inode);
  59
  60         if (strcmp(name, "") == 0)
  61                 return -EINVAL;
  62
  63         /* Convert Linux syscall to XFS internal ATTR flags */
  64         if (flags & XATTR_CREATE)
  65                 xflags |= ATTR_CREATE;
  66         if (flags & XATTR_REPLACE)
  67                 xflags |= ATTR_REPLACE;
  68
  69         if (!value)
  70                 return -xfs_attr_remove(ip, name, xflags);
  71         return -xfs_attr_set(ip, name, (void *)value, size, xflags);
  72 }
  73
  74 static struct xattr_handler xfs_xattr_user_handler = {
  75         .prefix = XATTR_USER_PREFIX,
  76         .flags  = 0, /* no flags implies user namespace */
  77         .get    = xfs_xattr_get,
  78         .set    = xfs_xattr_set,
  79 };
  80
  81 static struct xattr_handler xfs_xattr_trusted_handler = {
  82         .prefix = XATTR_TRUSTED_PREFIX,
  83         .flags  = ATTR_ROOT,
  84         .get    = xfs_xattr_get,
  85         .set    = xfs_xattr_set,
  86 };
  87
  88 static struct xattr_handler xfs_xattr_security_handler = {
  89         .prefix = XATTR_SECURITY_PREFIX,
  90         .flags  = ATTR_SECURE,
  91         .get    = xfs_xattr_get,
  92         .set    = xfs_xattr_set,
  93 };
  94
  95 struct xattr_handler *xfs_xattr_handlers[] = {
  96         &xfs_xattr_user_handler,
  97         &xfs_xattr_trusted_handler,
  98         &xfs_xattr_security_handler,
  99 #ifdef CONFIG_XFS_POSIX_ACL
 100         &xfs_xattr_acl_access_handler,
 101         &xfs_xattr_acl_default_handler,
 102 #endif
 103         NULL
 104 };
 105
 106 static unsigned int xfs_xattr_prefix_len(int flags)
 107 {
 108         if (flags & XFS_ATTR_SECURE)
 109                 return sizeof("security");
 110         else if (flags & XFS_ATTR_ROOT)
 111                 return sizeof("trusted");
 112         else
 113                 return sizeof("user");
 114 }
 115
 116 static const char *xfs_xattr_prefix(int flags)
 117 {
 118         if (flags & XFS_ATTR_SECURE)
 119                 return xfs_xattr_security_handler.prefix;
 120         else if (flags & XFS_ATTR_ROOT)
 121                 return xfs_xattr_trusted_handler.prefix;
 122         else
 123                 return xfs_xattr_user_handler.prefix;
 124 }
 125
 126 static int
 127 xfs_xattr_put_listent(struct xfs_attr_list_context *context, int flags,
 128                 char *name, int namelen, int valuelen, char *value)
 129 {
 130         unsigned int prefix_len = xfs_xattr_prefix_len(flags);
 131         char *offset;
 132         int arraytop;
 133
 134         ASSERT(context->count >= 0);
 135
 136         /*
 137          * Only show root namespace entries if we are actually allowed to
 138          * see them.
 139          */
 140         if ((flags & XFS_ATTR_ROOT) && !capable(CAP_SYS_ADMIN))
 141                 return 0;
 142
 143         arraytop = context->count + prefix_len + namelen + 1;
 144         if (arraytop > context->firstu) {
 145                 context->count = -1;    /* insufficient space */
 146                 return 1;
 147         }
 148         offset = (char *)context->alist + context->count;
 149         strncpy(offset, xfs_xattr_prefix(flags), prefix_len);
 150         offset += prefix_len;
 151         strncpy(offset, name, namelen);                 /* real name */
 152         offset += namelen;
 153         *offset = '\0';
 154         context->count += prefix_len + namelen + 1;
 155         return 0;
 156 }
 157
 158 static int
 159 xfs_xattr_put_listent_sizes(struct xfs_attr_list_context *context, int flags,
 160                 char *name, int namelen, int valuelen, char *value)
 161 {
 162         context->count += xfs_xattr_prefix_len(flags) + namelen + 1;
 163         return 0;
 164 }
 165
 166 static int
 167 list_one_attr(const char *name, const size_t len, void *data,
 168                 size_t size, ssize_t *result)
 169 {
 170         char *p = data + *result;
 171
 172         *result += len;
 173         if (!size)
 174                 return 0;
 175         if (*result > size)
 176                 return -ERANGE;
 177
 178         strcpy(p, name);
 179         return 0;
 180 }
 181
 182 ssize_t
 183 xfs_vn_listxattr(struct dentry *dentry, char *data, size_t size)
 184 {
 185         struct xfs_attr_list_context context;
 186         struct attrlist_cursor_kern cursor = { 0 };
 187         struct inode            *inode = dentry->d_inode;
 188         int                     error;
 189
 190         /*
 191          * First read the regular on-disk attributes.
 192          */
 193         memset(&context, 0, sizeof(context));
 194         context.dp = XFS_I(inode);
 195         context.cursor = &cursor;
 196         context.resynch = 1;
 197         context.alist = data;
 198         context.bufsize = size;
 199         context.firstu = context.bufsize;
 200
 201         if (size)
 202                 context.put_listent = xfs_xattr_put_listent;
 203         else
 204                 context.put_listent = xfs_xattr_put_listent_sizes;
 205
 206         xfs_attr_list_int(&context);
 207         if (context.count < 0)
 208                 return -ERANGE;
 209
 210         /*
 211          * Then add the two synthetic ACL attributes.
 212          */
 213         if (posix_acl_access_exists(inode)) {
 214                 error = list_one_attr(POSIX_ACL_XATTR_ACCESS,
 215                                 strlen(POSIX_ACL_XATTR_ACCESS) + 1,
 216                                 data, size, &context.count);
 217                 if (error)
 218                         return error;
 219         }
 220
 221         if (posix_acl_default_exists(inode)) {
 222                 error = list_one_attr(POSIX_ACL_XATTR_DEFAULT,
 223                                 strlen(POSIX_ACL_XATTR_DEFAULT) + 1,
 224                                 data, size, &context.count);
 225                 if (error)
 226                         return error;
 227         }
 228
 229         return context.count;
 230 }